CN102459935A

CN102459935A - Wheel bearing

Info

Publication number: CN102459935A
Application number: CN2010800269408A
Authority: CN
Inventors: 有竹恭大; 小森和雄
Original assignee: NTN Corp
Current assignee: NTN Corp
Priority date: 2009-06-18
Filing date: 2010-06-16
Publication date: 2012-05-16
Also published as: DE112010002565T5; WO2010147135A1; JP2011002030A; US20120148181A1

Abstract

Provided is a wheel bearing that prevents balls from becoming scratched and has improved acoustic properties and an improved lifespan. In the provided wheel bearing, which is configured as a double-row angular ball bearing, a counter area (18) is formed near a groove bottom of an inner rolling surface (13a) of an inner race (13), said counter area being larger than the groove bottom diameter (d1) by a 30-90 [mu]m clearance (2d) for forcing the balls into position. The counter area (18) comprises a cylindrical part (18a) that extends in the axial direction from the inner rolling surface (13a), and a tapered surface (18b) where the diameter decreases from the cylindrical part (18a) towards a small end surface (13b) of the inner race (13). The join area (A) where the counter area (18) and the inner rolling surface (13a) join is rounded into a circular arc having a radius of curvature R between 2.0 and 10.0. Since the counter area and the inner rolling surface (13a) are ground by a profile grinding wheel simultaneously, as a single unit, and are smoothly connected, it is possible to prevent balls (14) from becoming deeply scratched when vibrations occur during transit, even if there is repeated contact between the join area (A) and the balls (14).

Description

Wheel bearing

Technical field

The present invention relates to the wheel bearing that a kind of wheel that is used for the vehicle such as automobile supports with rotating freely, and relate more specifically to a kind ofly can prevent to form on the ball scratch or scratch and can improve the wheel bearing in acoustic characteristic and life-span.

Background technique

Traditionally, be used for the bearing apparatus for wheel that the wheel to vehicle supports with rotating freely and supply the hub wheel that wheel is used is installed, and bearing apparatus for wheel comprises the bearing apparatus for wheel that is used for driving wheel and is used for follower via roller bearings.Consider the structure of bearing apparatus for wheel, usually, the rotary-type driving wheel that is used to of inner ring all is used to follower and inner ring is rotary-type for rotary-type these two types with the outer ring.The bearing rigidity, opposing that have expectation in view of the biserial angular contact ball bearing with low torque characteristic be not to the high durability and the improved fuel efficiency of the heart, and the biserial angular contact ball bearing is widely used in the bearing apparatus for wheel.In the biserial angular contact ball bearing, be inserted with a plurality of balls between retainer ring and the rotation circle, and under the state that predetermined wrapping angle is applied to these balls, contact these balls.

Bearing apparatus for wheel broadly is divided into: the knuckle that the wheel bearing that comprises biserial angular contact ball bearing etc. is assembled in draft hitch forms the first generation type between part and the hub wheel; Car body mounting flange or wheel mounting flange are formed directly into the second generation type on the periphery of external member (outer ring); And interior raceway face is formed directly into the third generation type on the periphery of hub wheel.

In recent years,, also need to improve acoustic characteristic strongly except improving serviceability and reducing aspect the manufacture cost, that is, and " NVH ", just, " noise (Noise) ", " vibration (Vibration) " and " roughness (Harshness) ".As shown in Figure 8; The wheel bearing 50 of the existing technology of in bearing apparatus for wheel, using is formed by the biserial angular contact ball bearing; This biserial angular contact ball bearing for example comprises: outer ring 51, this outer ring are formed with

raceway face

51a, 51a outside the biserial on interior week; A pair of

inner ring

52,52, this to each inner ring in the inner ring on periphery, all be formed with biserial outside the relative interior raceway face 52a of raceway face outside among the

raceway face

51a, 51a one;

Biserial ball

53,53, these balls are accommodated between outer raceway face and the interior raceway face; And retainer 54, this retainer is used for keeping

biserial ball

53,53 with

rotatable mode.Sealing

55,56 is installed, to prevent to be sealed in the lubricant grease leakage in the bearing and to prevent that rainwater or dust from getting into bearing from the outside in the annular opening that is formed between outer ring 51 and the inner ring 52.

This wheel bearing 50 is called as first generation type, and is formed with convex (protuberance) 57 near the bottom portion of groove of the interior raceway face 52a at inner ring 52 as shown in Figure 9, and the outside diameter d 2 of this convex is greater than recess base diameter d1.This has prevented that inner ring 52 from coming off from wheel bearing 50 after assembling.This layout makes it possible to prevent ball 53 and convex 57 interference, and can prevent that it from coming off from inner ring 52.That is to say; Be accommodated under the situation in the bottom portion of groove of outer raceway face 51a of outer ring 51 at ball 53; The outside diameter d 2 of the convex 57 of inner ring 52 is greater than the inscribed circle diameter d0 of ball, and therefore formation so-called " ball lock height " (hereinafter referred is " gap ") 2 δ between said diameter " d2 " and " d0 ".

In addition, the periphery of the shoulder 52b of inner ring 52, interior raceway face 52a, convex 57 and ground by form grinder simultaneously than small end face 52c forms.This makes it possible to dimensional changes is reduced to minimum; And (promptly with gap 2 δ and " core distance L "; From the bottom portion of groove of interior raceway face 52a to distance than small end face 52c) be limited in the predetermined reference value so that minimum (for example referring to patent documentation 1) reduced in the variation of initial space setting value and bearing prepressing force power.

In general single-row angular contact ball bearing, if gap 2 δ are less, the assembling of bearing will become easily so, but inner ring will be easy to come off.On the other hand, if gap 2 δ are bigger, the assembling of bearing will become difficult so, and will produce ball scratch (scratch that in the process that is press fit into the crack, produces).In the wheel bearing 50 of existing technology; Because the interior raceway face 52a of inner ring 52 and convex 57 etc. are ground by form grinder and form and therefore gap 2 δ and core distance L are limited in the predetermined reference value; Change so can initial space setting value reduced to minimum and reduce precompression; And therefore can prevent in the bearing pack process of assembling, to produce the ball scratch, and can also prevent that inner ring 52 from coming off after the assembling bearing.

Yet in the wheel bearing 50 of existing technology, in the transportation process of bearing and in the number of assembling steps in the automobile making factory, ball 53 is easy to contact the edge of convex 57.When the impulsive load that produces owing to excessive vibration when ball 53 contacts convex 57, may on ball 53, form scratch.In addition, in the assembling process of bearing, when be configured as have straight shape convex 57 under the radially inner side of ball 53 through out-of-date, ball 53 sometimes may be by scratch.Because these scratches will make the acoustic characteristic of wheel bearing worsen, and the life-span that can reduce wheel bearing, therefore, adopted a kind of assembling method that can on ball, not produce scratch, but this method has increased the cost that makes wheels with bearing.

The applicant has proposed the automobile-used wheel bearing shown in a kind of Figure 10.The inner ring 58 of bearing means is formed with convex 59 at the bottom portion of groove annex of interior raceway face 52, and this convex has predetermined axial width and greater than the diameter of recess base diameter d1.Convex 59 comprises cylindrical portion 59a and tapered portion 59b, and cylindrical portion 59a extends axially from interior raceway face 52a, tapered portion 59b from cylindrical portion 59a towards than small end face 52c convergent and continuously to smaller diameter portion 60.The outside diameter d 2 of convex 59 is configured to make that under the situation outside ball 53 is accommodated in the bottom portion of groove of raceway face 51a, outside diameter d 2 is than big predetermined gap 2 δ (d2=d0+2 δ) of inscribed circle diameter d0 of ball 53.Inclination angle theta is set to the angle below 5 °.Transition portion A between interior raceway face 52a and the convex 59 is formed by the circular arc with predetermined bend radius R, and the bight between the cylindrical portion 59a of convex 59 and the tapered portion 59b is by circular arc cavetto and smooth and form continuously.Inclination angle theta allows ball 53 is guided to cylindrical portion 59a smoothly from tapered portion 59b, and therefore in the assembling process of bearing, suppresses the generation of scratch on the ball 53.In addition, the transition portion A that forms the circular arc with predetermined bend radius R can prevent to produce burr etc. and in the assembling process of inner ring 58, can prevent because gap and on ball, produce scratch.And, contact with convex 59 in the transportation process of bearing and in the number of assembling steps in automobile making factory because prevented ball 53, so can improve the acoustic characteristic and the life-span (for example referring to patent documentation 2) of wheel bearing.

The existing technology document

Patent documentation

Patent documentation 1: No. 193745/2001 patent gazette of TOHKEMY

Patent documentation 2: No. 085371/2007 patent gazette of TOHKEMY

Summary of the invention

Problem to be solved by this invention

In the bearing apparatus for wheel of third generation type, even in transportation process, there is vibration to be applied to bearing means, inner ring 58 does not contact ball 53 yet, and this is because bearing means is to be press fit under the state in the hub wheel at inner ring 58 to transport.Yet; Especially first or the bearing apparatus for wheel of second generation type in; Because the transition portion A between interior raceway face 52a and the convex 59 is formed by the circular arc with predetermined bend radius R, thus can prevent on inner ring 58, to produce burr, yet; Under the less situation of radius of curvature R, ball 53 may be owing to sustaining damage contacting repeatedly of generation between transition portion A and the ball 53 because of vibration in the transportation process.If the degree of depth of damage is bigger on the ball 53, when ball 53 rolls, will produce edge loading (excessive load) so on interior raceway face 52a, and the life-span of therefore reducing bearing.Correspondingly, important and necessary is to suppress the generation that damages on the ball.

Therefore, the purpose of this invention is to provide a kind of like this wheel bearing, this wheel bearing can prevent the generation such as scratch and abrasive damage, thereby can improve the acoustic characteristic and the life-span of wheel bearing.

The means of dealing with problems

In order to realize the object of the invention, according to first aspect, the invention provides a kind of wheel bearing, this wheel bearing comprises: external member, this external member are formed with raceway face outside the biserial on interior week; A pair of inner ring, each inner ring in the said a pair of inner ring on periphery, all be formed with said biserial outside raceway face is relatively arranged outside in the raceway face one interior raceway face; And the biserial ball, said biserial ball is contained between said outer raceway face and the said interior raceway face with ability free rolling mode via retainer; Said wheel bearing is characterised in that: in said, be formed with convex near the bottom portion of groove of raceway face, the diameter of this convex is than the big predetermined gap of recess base diameter; Said convex is formed by cylindrical portion and tapered portion, and said cylindrical portion extends axially from said interior raceway face, said tapered portion reducing than small end face from said cylindrical portion towards said inner ring; And said convex and said in transition portion between the raceway face be that the circular arc of R2.0 to 10.0 forms smoothly by radius of curvature.

In the wheel bearing that comprises the biserial angular contact ball bearing, because in said, be formed with convex near the bottom portion of groove of raceway face, the diameter of this convex is than the big predetermined gap of recess base diameter; Said convex is formed by cylindrical portion and tapered portion, and said cylindrical portion extends axially from said interior raceway face, said tapered portion reducing than small end face from said cylindrical portion towards said inner ring; And said convex and said in transition portion between the raceway face be that the circular arc of R2.0 to 10.0 forms smoothly by radius of curvature; So a kind of like this wheel bearing can be provided; This wheel bearing can prevent on ball, to produce darker damage; Therefore and acoustic characteristic and the life-span that can improve wheel bearing, also be like this even in transportation process, contact under the situation of transition portion repeatedly at ball owing to there is vibration to be applied to wheel bearing.

Preferably, according to a second aspect of the invention, the said gap of said convex is set in the scope of 30 to 90 μ m.Also can keep the enough anti-power of dropping even this makes there being impulsive load to be applied under the situation of inner ring, but also make it possible to assemble wheel bearing effectively and can not cause the hardness of the outer ring of bearing to reduce.

Preferably, according to a third aspect of the invention we, the transition portion between the said cylindrical portion of said convex and the bight of said tapered portion is formed by circular arc smoothly, and the inclination angle of said tapered portion is set to the angle below 5 °.This makes it possible to ball is guided to cylindrical portion smoothly from tapered portion, and therefore in the assembling process of inner ring, suppresses the generation of scratch on the ball.

Also preferably, according to a forth aspect of the invention, said convex and said interior raceway face are ground by the form grinder one simultaneously and are formed.Therefore this makes it possible to form the level and smooth convex that does not have the bight, and can guarantee to prevent the generation of burr etc.

Preferably, according to a fifth aspect of the invention, being ground by form grinder simultaneously than big periphery with than small end face of said inner ring forms.This makes it possible to the bottom portion of groove from interior raceway face is precisely defined in the predetermined reference value to the core distance than small end face, and therefore can be through the initial space setting value of bearing being reduced to the minimum variation that reduces bearing prepressing force power.

Also preferably; According to a sixth aspect of the invention; Said external member with said outside the bottom portion of groove position spaced apart by a predetermined distance of raceway face be formed with the convex that internal diameter is slightly less than recess base diameter; The scope of the said internal diameter of this convex is configured to make that the ball that is kept by said retainer can not come off from said retainer owing to the reducing of circumcircle diameter of this ball, and the transition portion between said convex and the said outer raceway face is that the circular arc of R2.0 to 10.0 forms smoothly by radius of curvature.This makes it possible to prevent to produce burr and on ball, produces darker damage; Therefore and acoustic characteristic and the life-span that can improve wheel bearing, also be like this even in transportation process, contact under the situation of transition portion repeatedly at ball owing to there is vibration to be applied to wheel bearing.

Preferably, according to a seventh aspect of the invention, said convex and said outer raceway face are ground by the form grinder one simultaneously and are formed.Therefore this makes it possible to form the level and smooth convex that does not have the bight, and burr such as can guarantee to prevent to produce and prevent in the assembling process of bearing, on ball, to produce scratch.

Also preferably, according to an eighth aspect of the invention, said outer raceway face and said interior raceway face are ground by form grinder simultaneously and are formed.This makes it possible to form smoothly transition portion, thereby improves the accuracy of the coaxality of the outer raceway face of biserial, internal diameter and convex, and can guarantee the groove height of expecting and prevent riding piggyback of ball, thereby can guarantee the predetermined age of bearing.

The invention effect

According to wheel bearing of the present invention, because this wheel bearing comprises: external member, this external member are formed with raceway face outside the biserial on interior week; A pair of inner ring, each inner ring in the said a pair of inner ring on periphery, all be formed with said biserial outside raceway face is relatively arranged outside in the raceway face one interior raceway face; And the biserial ball, said biserial ball is contained between said outer raceway face and the said interior raceway face with ability free rolling mode via retainer; Said wheel bearing is characterised in that: be formed with convex near the bottom portion of groove of raceway face in said, the diameter of this convex is than the big predetermined gap of recess base diameter; Said convex is formed by cylindrical portion and tapered portion, and said cylindrical portion extends axially from said interior raceway face, said tapered portion reducing than small end face from said cylindrical portion towards said inner ring; And said convex and said in transition portion between the raceway face be that the circular arc of R2.0 to 10.0 forms smoothly by radius of curvature; So; A kind of like this wheel bearing can be provided; This wheel bearing can prevent on ball to produce darker damage, and acoustic characteristic and life-span that therefore can wheel bearing, also is like this even in transportation process, contact under the situation of transition portion repeatedly owing to there is vibration to be applied to wheel bearing at ball.

Description of drawings

Fig. 1 shows the longitudinal sectional view of first mode of execution of bearing apparatus for wheel of the present invention.

Fig. 2 shows the longitudinal sectional view of the wheel bearing of Fig. 1.

Fig. 3 (a) is the partial enlarged drawing of the inner ring of Fig. 2, and Fig. 3 (b) is the further enlarged view of Fig. 3 (a).

Fig. 4 shows the explanatory drawing of the grinding process of inner ring.

Fig. 5 shows the figure of gap and the anti-relation between the power that drops.

Fig. 6 (a) is the enlarged view of the outer ring of Fig. 2, and Fig. 6 (b) is the further enlarged view of Fig. 6 (a).

Fig. 7 shows the explanatory drawing of the grinding process of outer ring.

Fig. 8 shows the longitudinal sectional view of the wheel bearing of existing technology.

Fig. 9 is the partial enlarged drawing of the inner ring of Fig. 8.

Figure 10 (a) is the partial enlarged drawing of the inner ring of existing technology, and Figure 10 (b) is the further enlarged view of Figure 10 (a).

Embodiment

A kind of pattern that is used for embodiment of the present invention is a kind of wheel bearing, and this wheel bearing comprises: outer ring, this outer ring are formed with raceway face outside the biserial on interior week; A pair of inner ring, each inner ring in the said a pair of inner ring on periphery, all be formed with said biserial outside raceway face is relatively arranged outside in the raceway face one interior raceway face; And biserial ball; Said biserial ball is contained between said outer raceway face and the said interior raceway face with ability free rolling mode via retainer; Said wheel bearing is characterised in that: in said, be formed with convex near the bottom portion of groove of raceway face, the diameter of this convex is than the big predetermined gap of recess base diameter; Said convex is formed by cylindrical portion and tapered portion, and said cylindrical portion extends axially from said interior raceway face, said tapered portion reducing than small end face from said cylindrical portion towards said inner ring; And said convex and said in transition portion between the raceway face be that the circular arc of R2.0 to R10.0 forms smoothly by radius of curvature, and with said in raceway face grind simultaneously by form grinder integratedly.

Mode of execution

Preferred embodiment describe of the present invention below with reference to accompanying drawings.

Fig. 1 is the longitudinal sectional view that first mode of execution of bearing apparatus for wheel of the present invention is shown; Fig. 2 shows the longitudinal sectional view of the wheel bearing of Fig. 1; Fig. 3 (a) is the partial enlarged drawing of the inner ring of Fig. 2, and Fig. 3 (b) is the further enlarged view of Fig. 3 (a); Fig. 4 shows the explanatory drawing of the grinding process of inner ring; Fig. 5 shows the figure of gap and the anti-relation between the power that drops; Fig. 6 (a) is the enlarged view of the outer ring of Fig. 2, and Fig. 6 (b) is the further enlarged view of Fig. 6 (a); And Fig. 7 shows the explanatory drawing of the grinding process of outer ring.In description of the invention, the outside of bearing apparatus for wheel is called " outside " (left side among the figure) in the time of will be on being installed to vehicle, and the inboard of bearing apparatus for wheel is called " inboard " (right side among the figure) will be on being installed to vehicle the time.

Shown bearing apparatus for wheel is the so-called first generation type that is used for driving wheel, and mainly comprises hub wheel 1 and wheel bearing 3, and this wheel bearing is press fit on the hub wheel 1 and is suitable for rotatably supporting hub wheel 1 with respect to knuckle 2.Hub wheel 1 is formed with on outboard end supply to install wheel mounting flange 4 that wheel W uses and from these wheel mounting flange 4 axially extended cylindrical portion 5.Wheel mounting flange 4 upper edge peripheries also are furnished with the hub bolt 4a that supplies to install wheel W and brake rotors B equidistantly.Hub wheel 1 also is formed with the sawtooth (or spline) 6 that is used for transmitting torque on interior week.Wheel bearing 3 is press fit on the periphery of cylindrical portion 5.

Hub wheel 1 is that 0.40～0.80% the middle-carbon steel such as S53C is processed by Kohlenstoffgehalt by weight, and passes through high-frequency induction hardening and harden, so that have the surface hardness of 50～64HRC to the zone of cylindrical portion 5 from the inside base of wheel mounting flange 4.This makes it possible to apply enough mechanical strengths and resists the rotating bending load that is applied to wheel mounting flange 4, and can improve the abrasion resistance properties that voltage supply cooperates the cylindrical portion 5 of wheel bearing 3 usefulness.

Wheel bearing 3 is fixed on the hub wheel 1, is clipped between the shoulder 9 and hub wheel 1 of the socket member 8 that forms constant velocity joint 7.Socket member 8 has formed from the axially extended bar of shoulder 9 portion 10, and this bar portion 10 is formed with the sawtooth (or spline) with sawtooth 6 couplings of hub wheel 1 on periphery, and is formed with external screw thread 10b.Be suitable for being passed to hub wheel 1 from the moment of torsion of motor via the sawtooth 10a of the bar portion 10 of live axle (not shown), constant velocity joint 7 and this constant speed universal joint 7.In addition, through set screw nut 11 being fastened on the external screw thread 10b of bar portion, and apply predetermined bearing prepressing force power to wheel bearing 3 with predetermined tightening torque.

Shown in the enlarged view of Fig. 2, wheel bearing 3 comprises: outer ring (external member) 12; Be assembled to a pair of

inner ring

13,13 in the outer ring 12; Be contained in the

biserial ball

14,14 between outer ring 12 and the inner ring 13, and this wheel bearing forms the biserial of the amphistyly back-to-back angular contact bearing of the mutual butt of anterior end surface of said a pair of

inner ring

13,13.

Outer ring 12 is formed by the high-carbon chromium steel such as SUJ2, and on interior week, is formed with

raceway face

12a, 12a outside the biserial.Each inner ring 13 is also formed by the high-carbon chromium steel such as SUJ2, and on periphery, be formed be suitable for outside raceway face is relatively arranged outside among the

raceway face

12a, 12a one interior raceway face 13a.

Biserial ball

14,14 is also formed by the high-carbon chromium steel such as SUJ2, and is accommodated between outer raceway face 12a and the interior raceway face 13a, and is kept by retainer 15 and 15.

Sealing

16,17 is installed, to prevent to be included in the grease leakage in the bearing and to prevent that rainwater and dust from getting into bearing from the outside at the two ends of wheel bearing 3.

Shown in the enlarged view of Fig. 3, the periphery of inner ring 13 is formed with convex 18 near the bottom portion of groove of interior raceway face 13a, the diameter that this convex 18 has predetermined width and is slightly larger than recess base diameter d1.Convex 18 is formed by cylindrical portion 18a and tapered portion 18b, and cylindrical portion 18a extends axially from interior raceway face 13a, and tapered portion 18b is 13 reduce than small end face 13b from cylindrical portion 18a towards inner ring, and continuous with the cylindrical portion with the diameter that further reduces 19.Transition portion (bight) between the cylindrical portion 18a of convex 18 and the tapered portion 18b is formed by circular arc smoothly.

The outside diameter d 2 of convex 18 is configured to make that under the situation outside ball 14 is accommodated in the bottom portion of groove of raceway face 12, outside diameter d 2 is than big predetermined gap 2 δ (d2=d0+2 δ) of inscribed circle diameter d0 of ball 14.Inclination angle theta is set to the angle below 5 °.The inclination angle theta of tapered portion 18b is set to the angle below 5 °.Inclination angle theta allows ball 14 is guided to cylindrical portion 18a smoothly from tapered portion 18b, and therefore can in the assembling process of bearing, suppress the generation of scratch on the ball 14.

According to the present invention, the transition portion A between interior raceway face 13a and the convex 18 is formed by the circular arc with predetermined bend radius R, and is formed by form grinder 21 (Fig. 4) grinding simultaneously with interior raceway face 13a.This makes it possible to the outside diameter d 2 of convex 18 is limited in the predetermined reference value, so that gap 2 δ of convex 18 are set in the predetermined tolerance, and can also be accurately and form the structure and the size of convex 18 smoothly.In addition; As shown in Figure 4, if big external diameter 20, convex 18 and ground by form grinder 21 simultaneously with interior raceway face 13a than small end face 13b forms, then can be with " core apart from "; Promptly;, be precisely defined in the predetermined reference value to distance from the bottom portion of groove of interior raceway face 13a, so that initial space setting value and bearing prepressing force power are reduced to minimum than small end face 13b.

The applicant has implemented several embodiments; In these embodiments; Transition portion A between interior raceway face 13a and the convex 18 has different curvature radii R; And through applying vibration to wheel bearing, the applicant has carried out damage and has produced test, and has verified the relation between the size of the damage of generation on radius of curvature R and the ball 14.Test result has been shown in the table 1.

Table 1

Sequence number	The radius of curvature of transition portion	Gap	2 δ	The degree of depth of ball damage
					1	R0.2	30μm	2.5μm
2	R0.5	110μm	2.5μm
				3	R2.0	30μm	0.8μm
4	R5.0	90μm	0.8μm
				5	R10.0	110μm	0.8μm
6	R12.0	110μm	0.8μm

As finding out from table 1, can be set in through radius of curvature R transition portion A R2.0 with on reduce the degree of depth of the damage of ball 14.If because radius of curvature R surpasses R10.0, then cylindrical portion 18a will shorten, and this does not expect, therefore the radius of curvature R with transition portion A is set in the scope of R2.0 to 10.0.This makes it possible to prevent the generation of burr etc., and can be through the outside diameter d 2 of grinding the utmost point to process convex 18 exactly simultaneously.In addition; A kind of like this wheel bearing can be provided; This wheel bearing can prevent on ball, to produce darker damage; Therefore and acoustic characteristic and the life-span that can improve wheel bearing, also be like this even in transportation process, contact under the situation of transition part A repeatedly at ball 14 owing to there is vibration to be applied to wheel bearing.

The chart of Fig. 5 shows the relation between the anti-power of dropping of gap 2 δ that produce owing to convex and inner ring 13.When only considering the anti-power of dropping of inner ring 13, although bigger gap 2 δ are effectively, under the bigger situation of gap 2 δ, the heating-up temperature that needs to increase outer ring 12 contacts the convex 18 of inner ring 13 so that prevent ball 14 in the assembling process of wheel bearing.This has increased the cycle of assembling, and causes the hardness of outer ring 12 to reduce, and does not therefore expect.Therefore, according to the present invention, 2 δ are set in the scope of 30 to 90 μ m with the gap.Even making, this under the situation that in this inner ring, produces bigger acceleration owing to there is impulsive load to be applied to inner ring 13, also can guarantee the enough anti-power of dropping; And therefore can implement effective assembling of bearing, and can not cause the reduction of outer ring 12 hardness.

On the other hand, shown in the enlarged view of Fig. 6, with the position of the spaced apart intended distance of bottom portion of groove of outer raceway face 12a, outer ring 12 is formed with convex 22, the inside diameter D 2 of this convex 22 is slightly less than recess base diameter D1.The scope of the inside diameter D 2 of convex 22 be configured to make the ball 14 that keeps by the retainer (not shown) not can owing to the circumcircle diameter D0 of this ball 14 reduce climb up convex 22 and therefore drop from retainer.

Be similar to inner ring 13, the transition portion B between outer raceway face 12a and the convex 22 is that the circular arc of R2.0 to 10.0 forms continuously and smoothly by radius of curvature.This makes it possible to prevent to produce burr; Even and ball 14 in transportation process owing to there is vibration to be applied to wheel bearing and to contact repeatedly under the situation of transition portion B; Also can prevent on ball 14, to produce darker damage, and acoustic characteristic and the life-span that therefore can improve wheel bearing.

As shown in Figure 7, convex 22 is ground simultaneously by form grinder 24 integratedly and forms with outer raceway face 12a, 12a.This makes it possible to form smoothly transition portion B; Prevent in the transportation process of wheel bearing, on ball 14, to produce scratch; Improve the accuracy of the coaxality of the outer raceway face 12a of biserial, 12a, internal diameter 23 and convex 22; And can guarantee the groove height of expecting and prevent that ball from riding shoulder, thereby can guarantee the predetermined age of bearing.In this manual; Term " is ridden shoulder " and is meant a kind of like this phenomenon; Wherein, When bearing bears big torque load, the contact ellipse that is formed at the contact segment between ball 14 and the outer raceway face 12a from internal diameter 23 and outside bight between the raceway face 12 stretch out and produce so-called edge loading.

With reference to preferred implementation the present invention has been described.Obviously, after reading and having understood preceding detailed description, those of ordinary skills can carry out multiple modification and substitute.The present invention is understood to include all such modification and substitutes, as long as they drop in the scope of accompanying claims or its equivalent.

Industrial applicibility

Wheel bearing of the present invention can be applied to the bearing apparatus for wheel of the first generation or second generation type, and whether to be used to driving wheel or follower irrelevant with it.

Description of reference numerals

1 hub wheel

2 knuckles

3 wheel bearings

4 wheel mounting flanges

4a hub bolt

5 cylindrical portion

6, the 10a sawtooth

7 constant velocity joints

8 socket members

9 shoulders

10 bar portions

11 set screw nuts

12 outer rings

The outer raceway face of 12a

13 inner rings

Raceway face in the 13a

13b is than small end face

14 balls

15 retainers

16,17 Sealings

The convex of 18 inner rings

The 18a cylindrical portion

The 18b tapered portion

19 less external diameters

20 big external diameters

21,24 glaze wheels

The convex of 22 outer rings

The internal diameter of 23 outer rings

50 wheel bearings

51 outer rings

The outer raceway face of 51a

52,58 inner rings

Raceway face in the 52a

The 52b shoulder

52c is than small end face

53 balls

54 retainers

55,56 Sealings

57 convexes

A, the B transition portion

The B brake rotors

The inscribed circle diameter of d0 ball

D0 circumcircle diameter

The recess base diameter of raceway face in the d1

The recess base diameter of the outer raceway face of D1

The external diameter of the convex of d2 inner ring

The internal diameter of the convex of D2 outer ring

The radius of curvature of R transition portion

The L core diameter

The W wheel

The Δ gap

The inclination angle of θ tapering part

Claims

1. wheel bearing, this wheel bearing comprises:

External member, this external member are formed with raceway face outside the biserial on interior week;

A pair of inner ring, each inner ring in the said a pair of inner ring on periphery, all be formed with said biserial outside raceway face is relatively arranged outside in the raceway face one interior raceway face; And

The biserial ball, said biserial ball is contained between said outer raceway face and the said interior raceway face with ability free rolling mode via retainer;

Said wheel bearing is characterised in that:

In said, be formed with convex near the bottom portion of groove of raceway face, the diameter of this convex is than the big predetermined gap of recess base diameter;

Said convex is formed by cylindrical portion and tapered portion, and said cylindrical portion extends axially from said interior raceway face, said tapered portion reducing than small end face from said cylindrical portion towards said inner ring; And

Said convex and said in transition portion between the raceway face be that the circular arc of R2.0 to 10.0 forms smoothly by radius of curvature.

2. wheel bearing as claimed in claim 1, wherein, the said gap of said convex is set in the scope of 30 to 90 μ m.

3. according to claim 1 or claim 2 wheel bearing, wherein, the said cylindrical portion of said convex and the transition portion between the said tapered portion are formed by circular arc smoothly, and the inclination angle of said tapered portion is set to the angle below 5 °.

4. like each described wheel bearing in the claim 1 to 3, wherein, said convex and said interior raceway face are ground by the form grinder one simultaneously and are formed.

5. wheel bearing as claimed in claim 4, wherein, the big periphery of said inner ring and said the grinding by form grinder simultaneously than small end face form.

6. like each described wheel bearing in the claim 1 to 5; Wherein, Said external member with said outside the bottom portion of groove position spaced apart by a predetermined distance of raceway face be formed with the convex that internal diameter is slightly less than recess base diameter; The scope of the said internal diameter of this convex is configured to make that the ball that is kept by said retainer can not come off from said retainer owing to the reducing of circumcircle diameter of this ball, and the transition portion between said convex and the said outer raceway face is that the circular arc of R2.0 to 10.0 forms smoothly by radius of curvature.

7. wheel bearing as claimed in claim 6, wherein, said convex and said outer raceway face are ground by the form grinder one simultaneously and are formed.

8. wheel bearing as claimed in claim 7, wherein, said outer raceway face and said interior raceway face are ground by form grinder simultaneously and are formed.